From sweat-sensing wristbands to
electrode-embedded workout suits, new innovations in smart clothing
are coming thick and fast. Now, Ohio State University
researchers have made another big breakthrough, managing to create
embroidered circuits using metallic thread that's just 0.1 mm thick.
By embedding different patterns, the tech could be used to create
everything from a t-shirt that boosts your cellphone signal, to a hat
that tracks brain activity.

Embroidery is not likely something that
you'd associate with cutting edge technology, but a new breed of
functional textiles, known as "e-textiles" are set to challenge that
perception. The concept makes use of
sewing machines capable of embroidering thread into fabric
automatically based on a pattern sent to it from a computer. But rather than traditional thread, fine metal wires are used.

The Ohio State researchers have been
working to refine the process for a couple of years, and have made
significant progress in that time. At the start of the project, the
team was working with silver-coated polymer thread measuring about
0.5 mm (0.02 in) across and made up of 600 fine filaments twisted
together.

They've since moved to a much thinner
alternative that's only made up of seven filaments, each with a
copper center and enameled with pure silver. The new thread is
thinner, but thanks to its materials, maintains high conductivity.
Because it's so thin, at just 0.1 mm, the resulting fabric
feels just the same as if traditional thread had been used, with none
of the rigidity you might initially expect.

So, how does that embedded metal wiring
translate to functional use? Well, it's all in the shape. Depending
on the pattern that's embroidered, it's possible to create many
different useful products. For example, a broadband antenna can be
created by embedding numerous interlocking geometric shapes that
together form a circular pattern measuring a few inches across. The
wiring required to produce that antenna only costs around 30 cents,
and the embroidery process reportedly takes just 15 minutes to complete.

The researchers have also used the embroidery technique to embedded an RFID chip in rubber – a part of a project undertaken in partnership with a tire manufacturer.

Looking forward, the team intends to
continue its work on smart clothing, and there are plans to license
the technology out, meaning that these sci-fi-sounding products might just become a purchasable reality somewhere down the line.

"A revolution is happening in the
textile industry," said director of the Ohio State University
laboratory John Volakis. "We believe that functional textiles are
an enabling technology for communications and sensing – and one day
even medical applications like imaging and monitoring."